By and large the majority of vacuum cleaner apparatus in current use for surface sweeping of floors, furniture and the like utilize a porous paper bag which can be readily disposed of when filled to capacity with dust and other debris. The function of the bag is to trap most of the vacuumed dust or dirt particles while returning the relatively clean air flow outward through the bag to the surrounding environment. While reconciled as adequate for most purposes, it is evident that the porous paper bag has a relatively low dust retention efficiency and is in fact deficient in the quality of cleaning actually provided.
The porosity quality of the bag is a key factor in determining the ability of the bag to trap dust particles such that selection of bag material at most represents a compromise in performance. That is, materials of high porosity tend to afford a minimum of dust retention permitting much of the more finer sifting dust particles to be recycled with the air flow through the bag and back to the environment. On the other hand, a low porosity material tends to afford a high rage of dust retention but adversely produces too great a pressure drop across the bag resulting in a reduced air flow and effectiveness of the vacuum. Even a new bag will, in a matter of minutes, begin to incur pore clogging that in turn impedes the air flow.
As an economy of operation, present vacuum cleaner bags are designed for use until about half or three fourths filled before a changeout is expected to be conducted by the operator. Many times, the need for changeout is overlooked or ignored. Moreover, it is customary to store the vacuum cleaner with partially filled bags still attached, thereby providing an opportunity for previously collected mold and germs to breed and be blown out with subsequent uses of the vacuum cleaner. The foregoing has to some extent been realized in connection with other vacuum retention systems known and disclosed for example in U.S. Pat. Nos. 890,514; 1,504,136; 1,561,928; and 2,539,687.